structure and bondingmagerezaacademy.sc.ke/wp-content/uploads/2017/03/structure-a… · a solid...

NAME INDEX NUMBER SCHOOL DATE

STRUCTURE AND BONDING 1. 1989 Q 6

The table below gives the distance between atoms (bond lengths) in halogenmolecules and the energies required to break the bonds (bond energies) betweenthe atoms.

Molecule Bond length (nm) Bond Energy (KJ Mol-1)Cl – Cl Br – Br I – I At – At

0.20 0.23 0.260.29

240 195 150

(i) Predict the energy required to break the At – At bond ...............................................................................................................................................

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.....(ii) What is the relationship between bond length and bond energy for the halogen

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...2. 1989 P1 A Q 8

A solid compound has a giant Ionic Structure. State and explain whether the compound has electricity in the solid state. ...............................................................................................................................................

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1©Pyramid Assignments 0722614502/0733494581 All subjects, All topics available

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3. 1989 Q 33c (c) Using dots (.) and crosses (X) to represent outermost elections, draw a diagram to show the bonding CCl.

4. 1991 P1A Q 21Using dot (.) and crosses (X) to represent electrons, draw a diagram which shows the bonding in phosphate molecule, PH3 (Atomic numbers: p = 15, H = 1) (1 mark)

5. 1993 Q 13

In terms of structure and bonding, explain why graphic conducts electricity while diamond does not (2 marks)

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...6. 1993 Q 23c

(a) Study the information given in the table below and answer the questions thatfollow: -


Formula ofcompound

NaCl MgCl2 AlCl3 SiCl4 PCl3 SCl2

B.P. (0C) 1470 1420 Sublimesat 1800C

60 75 60

M.P. (0C) 800 710 -70 -90 -80

(i) Give two chlorides that are liquids at room temperature. Give a reason for the answer (2

marks)...............................................................................................................................................

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(ii) Give a possible reason why AlCl3 has a much lower melting point that MgCl2 althoughboth Al and Mg are metals (1 mark)

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.. (iii) Which one of the chlorides would remain in liquid state for the highest temperatures

range? Show you arrive at your answer (2 marks)...............................................................................................................................................

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...7. 1994 P1A Q 14

When an electric current was passed through two molten substances M and N in different containers, the observations in the table below were made.

Molten M Conducts an electric current and is notdecomposed

Molten N Conducts an electric current and a gas isformed at one of the electrodes

Suggest the type of bonding present in substance M and N

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8. 1994 Q 1 P2 The table below gives elements represented by letters T, U, V, W, X, Y and their

atomic numbers

Element T U V W X YAtomic number 12 13 14 15 16 17Electron arrangement

Use the information in the table to answer the questions below: -(a) Complete the above table giving the electron arrangement of each of the elements


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...(b) In which period of the periodic table do these elements belong? Give a reason

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....(c) How does the atomic radius v compare with that of X? Explain

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....(d) Give the formula of the compound that could be formed between U and W

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..(e) What type of bonding will be present in a compound formed between T and Y?

Explain

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...(f) Arrange the species T,T,T, in increasing order of size

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....(g) Which of the ions X2+ and X2- is the most stable? Explain


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(h) Give the formula of: (i) An acidic oxide formed when one of the elements in the table is heated in air

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... (ii) A basic oxide formed when one of the elements in the table is heated in air

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9. 1996 Q 5 a) Using dots (.) and crosses (x) to represent electrons draw diagram to represent `

the bonding in: (i) NH3 (ii) NH4

+ (1 mark)

b) State why an ammonia molecule (NH3) can combine with H+ to form NH4+

(Atomic numbers: N=7 and H=1) (1 mark)


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10. 1996 Q 11 Complete the table below.

Species Number of neutrons ElectronsH

11. 1996 Q 4 P2 Study the table below and answer the questions that follow:

a) Complete the table by filling in this missing atomic numbers and atomic mass. (2

marks)b) Write the electron arrangement for the following ions (2

marks)Ca+

P3+

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c) What is the melting point of hydrogen in degrees Kelvin? (1 mark)

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...........d) Which of the allotropes of phosphorous has a higher density? Explain (2

marks)


Element Atomic number Relative atomic mass Melting point (oC)AluminiumCalciumCarbonHydrogenMagnesiumNeonPhosphorousSodium

1320

121015

27.040.012.01.024.3

31.023

8503730-259650-24944.2 (white)590 (red)

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.......................e) The mass numbers of three isotopes of magnesium are 24, 25 and 26.

What is the mass number of the most abundant isotope of magnesium? Explain (2marks)

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........................f) Give the formula of the compound formed between aluminium and carbon. (1

marks)

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g) Explain the difference in the melting points of magnesium and sodium. (2marks)

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12. 1998 Q 5 The table below shows some properties of substances C, D and E. Study it and answer the questions that follow.

Substance M.P (0C) Solubility in water Electrical solid state Conductivity molten state.

E -39 Insoluble Good goodD 1610 Insoluble Poor poorE 801 Soluble Poor good

Select substancea) With a giant molecular structure


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........................b) That is not likely to be an element

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13. 1998 Q 10 An ion of phosphorous can be represented as 31 P3-

15Draw a diagram to show the distribution of the electrons and the composition of the nucleus of the ion of phosphorous.

14. 1998 Q 11Diamond and graphite are allotropes of carbon. In terms of structure and bonding

Explain the following. (a) Diamond is used in drilling through hard rocks

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.................................................... (b) Graphite is used as a lubricant

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15. 1998 Q 7d Study the information given in the table below and answer the questions that follow.

The letters do not represent the actual symbols of the elements

(d) What type of bond would exists in the compound formed when U and T react?

Give a reason for your answer

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.........................16. 1999 Q 6

What type of bond is formed when lithium and fluorine react? Explain (Atomic numbers: Li = 3 and F = 9)

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.......................17. 1999 Q 25

When solid magnesium carbonate was added to a solution of hydrogen chloride in methylbenzene, there was no apparent reaction. On addition of water to the resulting mixture, there was vigorous effervescence. Explain these observations

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18. 1999 Q 3e P2 Study the information in the table below and answer the questions that follow. The letters do not represent the symbols of the elements.


Element Atomic number Boiling pointSTUVW

313161819

16032743718871047

Element(C) Atomic number Melting pointLMNQR

1113141719

97.8660144040163.7

e) Using dots(.) and crosses (x) to represent outermost electrons show bonding in the compound formed elements N and Q.

19. 2000 Q 16 Compound Q is a solid with a giant ionic structure. In what form would the compound conduct an electric current

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20. 2000 Q 6a P2 (a)The following diagrams show the structures of two allotropes of carbon. Study them and answer the questions that follow

(i) Name allotrope

M ................................................................................................N.................................................................................................

(ii) Give one use of N


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.......................... (iii) Which allotrope conducts electricity? Explain

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21. 2001 Q 23 The table below shows the properties of substances K, L, M and N the substances

which are likely to be:

a) Copper metal.......................................................................................................b) Magnesium chloride..........................................................................................

22. 2002 Q 16

With reference to iodine, distinguish between covalent bonds and Van Der Waals forces

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Substances Reaction with oxygen at 25oC Melting point ConductivitySolid

Molten

KLMN

UnreactiveReactiveUnreactiveUnreactive

Low

HighLow

Poor

GoodGood

Good

GoodGood

23. 2002 Q 20The table below gives some information about the electrical conductivity and the likely bonding in substances N,P and Q. Complete the table by inserting the missing information the spaces numbered I, II and III

Substance Likely type of bonding present

Electrical solid Conductivity

N Metallic I………………… Conducts

P II……………………. Does not conduct ConductsQ III …………………… Does not conduct Does not conduct

24. 2003 Q 1b P2 b) i) Element A is the same group of the periodic table as chlorine.

Write the formula of the compound formed when A reacts with potassium metal. (1

mark)

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.......................... ii) What type of bonding exists in the compound formed in (b) (i) above?

Give a reason for your answers. (3 marks)

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25. 2004 Q 6Both diamond and graphite have giant atomic structures. Explain why diamond is hard while graphite is soft. (3 marks)

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26. 2005 Q 4Using dots (.) and crosses(x) to represent electrons, show bonding in the compoundsformed when the following elements react: (Si = 14, Na = 11 and Cl = 17) (1 mark)

a) Sodium and chlorine (1 mark)

b) Silicon and chlorine (1 mark)

27. 2005 Q 4c P2 (c)The table below gives some properties of substances I, II, III, and IV. Study it and answer the questions that follow

Substance Electrical conductivity M.P (0C) B.P (0C)Solid Molten

I Does not conduct Conducts 801 1420II Conducts Conducts 650 1107III Does not conduct Does not conduct 1700 2200IV Does not conduct Does not conduct 113 440

(i) What type of bonding exists in substances I and II (2 marks)


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............. (ii) Which substance is likely to be sulphur? Explain (2 marks)

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28. 2006 Q 20 a) Distinguish between a covalent bond and a co-ordinate bond (2 marks)

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....................... b) Draw a diagram to show bonding in an ammonium ion. (1 mark)

29. 2006 Q 3a,b P2 a) Distinguish between isotopes and allotropes. (2

marks)

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AC D E

B

b) The chart below is part of the periodic table. Study it and answer the questions that follow.(The letters are not the actual symbols of the elements).

i) Select the element in period three which has the shortest atomic radius. Give a reason for you answer. (2 marks)

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.............ii) Element F has the electronic structure, 2.8.18.4 on the chart above;

indicate the position of element F. (1 mark)

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.............iii) State one use of the elements of which E is a member. (1

mark)

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30. 2007 Q 3b b) In terms of structure and bonding, explain why the boiling point of chlorine is

lower than that of iodine. (2 marks)

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31. 2007 Q 29 The diagram below is a section of a model of the structure of element T.

a) State the type of bonding that exists in T. (1 mark)

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...........b) In which group of the period table does element T belong? Give a reason. (2 marks)

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32. 2007 Q 5a-c P2(a) The diagram below represents part of the structure of a sodium chloride crystal.

The position of one of the sodium ions in the crystal is shown as

(i) On the diagram, mark the position of the other three sodium ions (2 marks)

(ii) The melting and boiling points of sodium chloride are 8010C and 14130C respectively. Explain why sodium chloride does not conduct electricity at 250C, but does so at temperatures between 8010 C and 14130C (2

marks)


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....................... (b) Give a reason why ammonia gas is highly soluble in water (2 marks)

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.............(c) The structure of an ammonia ion is shown below:

Name the type of bond represented in the diagram by N → H (1 mark)

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33. 2008 Q 2b P2 b) The table below gives information about elements A1A2A3, and A4

Element Atomic Number

Atomic Radius (nm)

Ionic radius (nm)

A1

A2

A3

A4

351317

0.1340.0900.1430.099

0.0740.0120.0500.181

(i) In which period of the periodic table is element A2? Give a reason (2 marks)

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............. (ii) Explain why the atomic radius of:

I A1 is greater than that of A2;.......................................................................................................................

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..........................II A4 is smaller than its ionic radius (2

marks).......................................................................................................................

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.......................... (iii) Select the element which is in the same group as A3 (1 mark)

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......... (iv) Using dots (.) and crosses(x) to represent outermost electrons. Draw a

diagram to show the bonding in the compound formed when A1 reacts with A4

(1 mark)

34. 2009 Q 6a, c P2(a) Study the table below and complete it. (W- and X4+ are not the actual symbols of the icons)

Ion Number of Protons

Number of neutrons

Mass Number Electron Arrangement

W- 20 2.8.8

X4+ 14 28


(c) The atomic numbers of Na and Mg are 11 and 12 respectively. Which of the element has higher ionization energy? Explain (2 marks)

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35. 2009 Q 5In terms of structure and bonding, explain why the melting point of oxygen is muchlower than that of sodium. (3 marks)

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...36. 2009 Q 8

Using dots (.) and crosses (X) ,show bonding in: (a) The compound formed when nitrogen reacts with fluorine.

(Atomic numbers F= 9, N=7)...................................................................................................................................

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... (b) Sodium oxide (Atomic numbers Na = 11,O= 8)

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37. 2010 Q 14Using electrons in the outermost energy level, draw the dot (.) and cross (x) diagram for the molecules H2O and C2H4. (H = 1, C = 6, O = 8)

(2 marks)i) H2O


ii) C2H4

b) The formula of a complex ion is Zn(NH3)42+. Name the type of bond that is

likely to exist between zinc and ammonia in the complex ion. ...............................................................................................................................

38. 2010 Q 27The atomic numbers of phosphorus, sulphur and potassium are 15, 16 and 19 respectively. The formulae of their ions are P3-, S2- and K+. These ions have the same number of electrons.

Write the electron arrangement for the ions. (1 mark)

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a) Arrange the ions in the order of increasing ionic radius starting with the smallest. Givea reason for the order. (2 marks)

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39. 2010 Q 3 P2Use the information in the table below to answer the questions that follow. The letters do not represent the actual symbols of the elements.

Element Atomicnumber

Melting point (0C)

RSTUVW

111215171819

97.8650.044.0-102-18964.0

a) Give the reasons why the melting point of:i) S is higher than that of R (1 mark)

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ii) V is lower than that of U (2 marks)...................................................................................................................................

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b) How does the reactivity of W with chlorine compare with that of R with chlorine? Explain, (2 marks)...............................................................................................................................................

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c) Write an equation for the reaction between T and excess oxygen (1 mark)...................................................................................................................................

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d) When 1.15g of R was reacted with water, 600cm3 of gas was produced.Determine the relative atomic mass of R. (Molar gas volume = 24000cm3) (3 marks)

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e) Give one use of element V (1 mark)...............................................................................................................................................

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40. 2011 Q 5b(iii-vii) P2b) The table below gives the number of electrons, protons and neutrons in particles

A, B, C, D, E, F and G.

Particle Protons Electrons NeutronsA 6 6 6B 10 10 12C 12 10 12D 6 6 8E 13 10 14


F 17 17 18G 8 10 8

iii) Write the formula of the compound formed when E combines with G. (1 mark)...................................................................................................................................

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iv) Name the type of bond formed in (iii) above (1 mark)...................................................................................................................................

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v) How does the radii of C and E compare? Give a reason. (2 marks)...................................................................................................................................

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vi) Draw a dot (.) and cross (x) diagram for the compound formed between A and F. (1 mark)

vii) Why would particle B not react with particle D? ( 1 mark)

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41. 2011 Q 28 The diagram below shows the bonding between aluminum chloride and ammonia.

H Cl

H N Al Al

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©Pyramid Assignments 0722614502/0733494581 All subjects, All topics available

H Cl

a) Name the types of bonds that exist in the molecule. (1 mark)...................................................................................................................................

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b) How many electrons are used for bonding in the molecule? (1 mark).........................................................................................................................................

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42. 2012 Q7 P1 Ammonium ion has the following structure:

Label on the structure (a) Covalent bond; (1 mark) (b) Coordinate (dative) bond, (1 mark)


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